<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        .box1{
            width: 200px;
            height: 200px;
            background-color: pink;
            border: 1px solid red;
        }

        .box2{
            width: 100px;
            height: 100px;
            background-color: skyblue;
            margin-top: 20px;
        }
    </style>
</head>
<body>

内部div  会带着全部往下移动

<div class="box1">
    <div class="box2"> </div>
</div>
</body>
</html>
